BIRMINGHAM, Al. (WVTM) - A 10-year-old boy is dead, his mother in critical condition and three siblings are injured after a large sign fell on them in the new terminal at the Birmingham-Shuttlesworth International Airport this afternoon.

According to Toni Herrera, spokesperson for the airport, the family was on the northeast side of the building around 1:30 when the sign fell on them.

The sign was estimated to weigh 300 to 400 pounds, and took multiple people to lift off of the family, according to Donald Jones with Birmingham Fire and Rescue.

The mother, Heather Bresette, was transported to the University of Alabama at Birmingham Hospital, and the four children were transported to Children's Hospital. Luke Bresette, 10, was pronounced dead this afternoon according to the Jefferson County Coroner.

It's unclear at this time if the family was going to catch a flight or to greet someone at the airport.

Herrera said the airport doesn't know how this happened, but they are investigating the situation. The airport continues to be open, but the area in which the incident happened is currently closed.

"I have offered our full support to the Airport Authority as they investigate what has occurred this afternoon. I have asked our public safety staff to assist this family in their time of need in any way possible as they grapple with what has happened," said Birmingham Mayor William Bell.

The area of the terminal in which the incident occurred opened last week.